The invention concerns a drive device for a moveable furniture part, in particular for a drawer, comprising an ejection device having an ejection force storage member for ejecting the moveable furniture part into an open position, and a retraction device having a retraction force storage member for retracting the moveable furniture part from an open position into a closed position. In addition, the invention concerns an article of furniture comprising a furniture carcass and a moveable furniture part, wherein the moveable furniture part is moveable by such a drive device.
In furniture design and construction, in particular in fitment design and construction, a wide range of different aids and methods have already been known for many years, to make opening and closing of the moveable furniture parts easier for a user of articles of furniture. Thus, opening devices (so-called ejection devices or touch-latch mechanisms) have already been known for many decades, in which the moveable furniture part is ejected and thus opened by pressing on the moveable furniture part.
In order not just to facilitate the opening movement for a user, retraction devices have already been known for many years, which pull the drawer closed of its own accord, in particular in the last part of the closing travel. That guarantees that the moveable furniture part is reliably closed. In addition, damping devices are also used to prevent an excessively heavy impact and thus prevent damage if a drawer is pushed violently closed.
A fundamental problem with drive devices or articles of furniture having an ejection device and a retraction device is that the forces of the respective force storage member for ejection and for retraction respectively act in opposition to each other. In other words, it is necessary to ensure with suitable mechanical means that on the one hand a reliable locking action is afforded, while on the other hand the respectively correct force storage member acts at the correct moment in time and in the correct portion. An important aspect in this technical field is also where and by whom or what the respective force storage member (spring) is stressed or loaded. In many cases, the ejection force storage member is loaded by the operator for example when opening or closing the drawer. For loading the retraction force storage member, it is also possible for the user to apply the necessary stressing force by way of the drawer itself, or the retraction force storage member is stressed by the ejection force storage member itself as the ejection force storage member has a greater amount of energy (spring force) than the retraction force storage member.
An example of a retraction spring which is stressed upon opening by the ejection spring is disclosed in DE 198 23 305 A1. Stressing of the retraction spring by hand is described for example in DE 20 2009 009 566 U1. In both those devices the ejection spring is respectively stressed by hand in the closing movement.
A variant in which only one spring functions both as the ejection spring and also as the retraction spring is disclosed in WO 2011/143682.